In the area of peroxide disinfection of surfaces, residual peroxide must be removed from the disinfected surface due to sensitivity of other materials with which the disinfected surface comes in contact. This is especially so in the contact lens disinfection area where the disinfected lens will be placed directly on the eye. In the past, this has been accomplished by methods such as dilution with large volumes of water or saline or exposing the solution and/or disinfected material to a hydrogen peroxide decomposing agent or catalyst for a time sufficient to reduce the residual hydrogen peroxide to acceptable levels. Unfortunately, in many settings, especially in the contact lens field, dilution is not a commercially viable or user practical alternative. Furthermore, where the decomposition agent or catalyst is used, the regimen becomes bothersome in the number of steps involved and the degree of user involvement necessary. As the complexity of the regimen goes up, strict compliance with that regimen drops off dramatically. Hence, more user friendly single step processes have been attempted. Most notable and relevant to the instant invention in current use in the AO Sept system. This system operates by placing a contact lens to be disinfected in contact with a solution of peroxide and a platinum disk whereby peroxide disinfection and decomposition occur essentially simultaneously. The only user input is to place the components in the system and wait the appropriate time interval before removing the lenses.
Unfortunately, many times users do not follow the regimen sufficiently so that there is the risk that complete disinfection has not occurred or decomposition has not sufficiently taken place.
In a typical hydrogen peroxide system in which the hydrogen peroxide is contacted with hydrogen peroxide with the simultaneous introduction of contact lenses for disinfection, the hydrogen peroxide depletes rapidly and the disinfection at the higher concentrations is short. For example, in an AO Sept system in which the initial concentration of hydrogen peroxide is 3%, the concentration of the hydrogen peroxide falls rapidly to about 0.1% in about 12.5 minutes. After this point, the concentration decreases very slowly and it takes several hours, i.e. up to 8 hours or more, before the hydrogen peroxide is depleted sufficiently to ocularly safe or acceptable levels whereby the contact lens can be inserted into the eyes without fear of irritation or injury.
In some instances, it is desirable, however, to control the catalytic reaction of the hydrogen peroxide such that concentration of the hydrogen peroxide is high over a longer transition period and ideally to control the system so that the hydrogen peroxide concentration can be maintained at high levels for a longer period of time and then abruptly reduced to ocularly acceptable levels. This longer transition time is especially important where the materials to be disinfected are heavily contaminated. There is, therefore, a need for an improved hydrogen peroxide disinfectant system which makes it possible to control the decomposition rate of the hydrogen peroxide.